#[non_exhaustive]pub enum EmptyTargetResolutionMode {
Fail,
Skip,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against EmptyTargetResolutionMode, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let emptytargetresolutionmode = unimplemented!();
match emptytargetresolutionmode {
EmptyTargetResolutionMode::Fail => { /* ... */ },
EmptyTargetResolutionMode::Skip => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when emptytargetresolutionmode represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant EmptyTargetResolutionMode::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
EmptyTargetResolutionMode::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str on it yields "NewFeature".
This match expression is forward-compatible when executed with a newer
version of SDK where the variant EmptyTargetResolutionMode::NewFeature is defined.
Specifically, when emptytargetresolutionmode represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on EmptyTargetResolutionMode::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
Fail
Skip
Unknown(UnknownVariantValue)
Unknown. See the docs on this enum for the correct way to handle unknown variants.Unknown contains new variants that have been added since this code was generated.
Implementations§
source§impl EmptyTargetResolutionMode
impl EmptyTargetResolutionMode
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for EmptyTargetResolutionMode
impl AsRef<str> for EmptyTargetResolutionMode
source§impl Clone for EmptyTargetResolutionMode
impl Clone for EmptyTargetResolutionMode
source§fn clone(&self) -> EmptyTargetResolutionMode
fn clone(&self) -> EmptyTargetResolutionMode
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for EmptyTargetResolutionMode
impl Debug for EmptyTargetResolutionMode
source§impl From<&str> for EmptyTargetResolutionMode
impl From<&str> for EmptyTargetResolutionMode
source§impl FromStr for EmptyTargetResolutionMode
impl FromStr for EmptyTargetResolutionMode
source§impl Hash for EmptyTargetResolutionMode
impl Hash for EmptyTargetResolutionMode
source§impl Ord for EmptyTargetResolutionMode
impl Ord for EmptyTargetResolutionMode
source§fn cmp(&self, other: &EmptyTargetResolutionMode) -> Ordering
fn cmp(&self, other: &EmptyTargetResolutionMode) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq for EmptyTargetResolutionMode
impl PartialEq for EmptyTargetResolutionMode
source§fn eq(&self, other: &EmptyTargetResolutionMode) -> bool
fn eq(&self, other: &EmptyTargetResolutionMode) -> bool
self and other values to be equal, and is used
by ==.source§impl PartialOrd for EmptyTargetResolutionMode
impl PartialOrd for EmptyTargetResolutionMode
source§fn partial_cmp(&self, other: &EmptyTargetResolutionMode) -> Option<Ordering>
fn partial_cmp(&self, other: &EmptyTargetResolutionMode) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self and other) and is used by the <=
operator. Read moreimpl Eq for EmptyTargetResolutionMode
impl StructuralPartialEq for EmptyTargetResolutionMode
Auto Trait Implementations§
impl RefUnwindSafe for EmptyTargetResolutionMode
impl Send for EmptyTargetResolutionMode
impl Sync for EmptyTargetResolutionMode
impl Unpin for EmptyTargetResolutionMode
impl UnwindSafe for EmptyTargetResolutionMode
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.